1. Field of the Invention
This invention relates to methods of manufacturing pavers and, in particular, to methods of manufacturing photoluminescent pavers at a paver manufacturing facility.
2. Background Art
Paving blocks (i.e. pavers) are used for walkways, driveways and paths. The paving blocks allow ground motion without cracking which commonly occurs with concrete slabs and can be laid in various patterns that are aesthetically pleasing. Walkway lighting has long been used along with such paving blocks to increase safety and make for more sure footing or parking. Because the majority of walkway lighting is wired with low voltage electricity, there are electrical consumption costs associated with the use of such a system and difficulties in setup if the walkway is a long one or is located at a distance from an electrical outlet.
As described in U.S. Pat. No. 5,292,221, in automated brick or block making plants, a block machine presses moldable product into a block mold to produce green or uncured blocks. The green blocks are transported to kilns for curing and are thereafter palletized for shipment from the plant.
The block molding machine may dispense a plurality of green blocks on a rectangular metal pallet. The pallets are transported by conveyor to a stacker tower which receives the pallets, one at a time. After a pallet is received by the stacker at the level of the conveyor, the stacker shifts the pallet upwardly and then receives another pallet loaded with block directly therebeneath. This process continues until a vertical stack of pallets are held by the stacker.
The stacker is positioned adjacent a device known as a loader. The loader comprises a vertically-shiftable spade assembly from which a plurality of spades, positioned one above the other, extend laterally. There are the same number of spades in the loader as pallets with the spades being spaced apart from one another the same distance as the pallets in the stacker.
In operation, when the stacker is filled with loaded pallets, the loader carriage drives the spade assembly toward the stacker until each spade is received just beneath a corresponding pallet. One of the rams on the spade assembly actuates to shift the spades upwardly thereby lifting the pallets. The carriage then withdraws from the stacker, rotates 180° and advances toward a rack positioned at the other end of the spade assembly travel path. The carriage moves the spade assembly bearing the loaded pallets into the rack and a ram on the spade assembly actuates thereby lowering the assembly and depositing the stacked pallets on the rack.
Thereafter, either by way of a forklift or on automated transport cars, the racks are moved into kilns for curing.
After the blocks are cured, the racks are removed from the kilns and transported to a second stacker and unloader which operate in reverse fashion from the stacker and loader as described above and are referred to as an unloader and unstacker. The unloader carriage moves toward the rack bearing the cured block and positions a spade under each pallet. The ram on the spade assembly actuates thereby raising the spade assembly and the corresponding pallets which are then transported laterally by the unloader carriage toward the unstacker. Prior to reaching the unstacker the spade rotates 180° and thereafter drives into the unstacker and deposits the pallets thereon. The unstacker lowers each pallet, one at a time, onto a conveyor which transports the cured block to a palletizing station prior to shipment.
U.S. Pat. No. 6,665,986 discloses a phosphorescent paving block having a paving base, and a phosphorescent material in contact with the paving base. Additionally, the paving block can also have a light-transmitting cover and a light-transmitting base on either side of the phosphorescent material to form a laminate.
U.S. published patent application 2009/0262514 discloses a path marking system comprising a substrate defining cavity. A photoluminescent insert comprises a first resinous layer that is cast with photoluminescent particles suspended therein. Adhesive attaches the photoluminescent insert inside of the cavity. A marking device comprises a photoluminescent insert comprising cast resinous layers. A first one of the cast resinous layers includes photoluminescent particles suspended therein. A fastener includes a first portion cast in the photoluminescent insert and a second portion extending outside of the photoluminescent insert.
Other related U.S. patent documents include the following: 2007/0248836; 2009/0302760; 2009/0265979; 2005/0160637; 2006/0162620; U.S. Pat. Nos. 7,371,441; 6,627,315; 6,500,543; 7,066,680; 7,074,345; 6,309,562; 6,136,226; and 6,599,444.
U.S. patent publication 2008/007253 discloses a method and system for producing coated ballast pavers. A concrete mixture is shaped into uncured pavers. A reflective coating is applied to the top surface of the pavers. The uncured pavers and the coating are heated in a kiln to cure the concrete mixture and the reflective coating.
U.S. Pat. No. 7,364,615 discloses a method of forming pavers containing waste glass particles.